In general, a porous ceramic artificially form a large number of pores inside a ceramic and are used as lightweight construction materials within the specified extent because of its low specific gravity and lightness in weight. Moreover, the porous ceramic is variously used as various kinds of filters, instrumental materials for firing, deodorizers, heat insulating materials, soundproofing materials and heating materials.
In this porous ceramic heating element and method of manufacturing thereof, the following porous ceramic heating element and method of manufacturing thereof are generally used according to the related art.
First, the related art porous ceramic heating element is the mixture of aluminosilicate hydrogel, ceramic powder such as a carbide, a nitride and an oxide, 0.1 to 0.2% of aluminum particles, 0.4 to 0.8% of silicon glycol as a surface active agent, and 1 to 4% of silica as a gel strengthening agent.
In the method of manufacturing this porous ceramic heating element, after metal in the form of powder reacts to alkali solution, the mixture is put in aluminate slurry and molded in desired shape.
In that case, the molded product becomes the porous ceramic heating element while hydrogen is generated from the molded product. After that, the porous ceramic heating element is washed to remove the alkali and sintered, thereby obtaining the desired porous ceramic heating element.
However, the related art porous ceramic heating element have disadvantages that the bonding strength of pores formed inside is so weak that the mechanical strength of the structure of the porous ceramic heating element generally becomes weak, and the ability of storing heat is decreased.
Further, in the methods of manufacturing the related art porous ceramic heating element, an organic material is mixed with ceramic slurry, and then firing process is followed, thereby obtaining porosity.
However, if the porous ceramic heating element is heated in a high temperature, such porous ceramic heating element generates a poisonous gas carbonizing an added organic foaming agent.
In addition, the porous ceramic heating element has disadvantages of shape restriction and economic difficulty due to a high sintering temperature of over 1100° C. and a process complexity.